Nationwide Study of the Treatment of Mycotic Abdominal Aortic Aneurysms Comparing Open and Endovascular Repair

Background: No reliable comparative data exist between open repair (OR) and endovascular aneurysm repair (EVAR) for mycotic abdominal aortic aneurysms (MAAAs). This nationwide study assessed outcomes after OR and EVAR for MAAA in a population-based cohort. Methods: All patients treated for MAAAs in Sweden between 1994 and 2014 were identified in the Swedish vascular registry. The primary aim was to assess survival after MAAA with OR and EVAR. Secondary aims were analyses of the rate of recurrent infections and reoperations, and time trends in surgical treatment. Survival was analyzed using Kaplan-Meier and log-rank tests. A propensity score-weighted correction for risk factor differences in the 2 groups was performed, including the operation year to account for differences in treatment and outcomes over time. Results: We identified 132 patients (0.6% of all operated abdominal aortic aneurysms in Sweden). Mean age was 70 years (standard deviation, 9.2), and 50 presented with rupture. Survival at 3 months was 86% (95% confidence interval, 80%-92%), at 1 year 79% (72%-86%), and at 5 years 59% (50%-68%). The preferred operative technique shifted from OR to EVAR after 2001 (proportion EVAR 1994-2000 0%, 2001-2007 58%, 2008-2014 60%). Open repair was performed in 62 patients (47%): aortic resection and extra-anatomic bypass (n=7), in situ reconstruction (n=50), and patch plasty (n=3); 2 patients died intraoperatively. EVAR was performed in 70 patients (53%): standard EVAR (n=55), fenestrated/branched EVAR (n=8), and visceral deviation with stent grafting (n=7); no deaths occurred intraoperatively. Survival at 3 months was lower for OR than for EVAR (74% versus 96%, P<0.001), with a similar trend present at 1 year (73% versus 84%, P=0.054). A propensity score-weighted risk-adjusted analysis confirmed the early better survival associated with EVAR. During median follow-up of 36 and 41 months for OR and EVAR, respectively, there was no difference in long-term survival (5 years 60% versus 58%, P=0.771), infection-related complications (18% versus 24%, P=0.439), or reoperation (21% versus 24%, P=0.650). Conclusion: This study demonstrates a paradigm shift in treatment of MAAA in Sweden, with EVAR being the preferred treatment modality. EVAR was associated with improved short-term survival in comparison with OR, without higher associated incidence of serious infection-related complications or reoperations.